Blue Screen Errors on Windows: What They Mean and How to Fix Them

By the MyPCGuide Team · Updated November 2026 · 7 min read

A blue screen (formally a "stop error") appears when Windows hits a problem it cannot safely recover from. It is alarming, but a single blue screen is often a one-off. Repeated ones need investigation.

Write down the details

Note the stop code shown on screen, such as CRITICAL_PROCESS_DIED or IRQL_NOT_LESS_OR_EQUAL. It points toward the cause.

Common causes

• A faulty or incompatible driver
• Recent software or update changes
• Failing memory (RAM) or storage drive
• Overheating
• Corrupted system files

Troubleshooting plan

1. Remove recent changes. Uninstall software or hardware you added just before the problems began.
2. Install updates. Run Windows Update, including optional driver updates.
3. Run system file check. In an administrator Command Prompt run sfc /scannow, then DISM /Online /Cleanup-Image /RestoreHealth.
4. Test memory. Use Windows Memory Diagnostic.
5. Check storage health and free space. See our PC health check guide.
6. Check temperatures and dust. Clean vents if needed.
7. Use System Restore to return to a date before the problem began.

If Windows will not start

After a few failed starts, Windows opens the Recovery Environment, where you can use Startup Repair, System Restore or Safe Mode.

Protect your data first

If blue screens continue, back up your files right away. Read the 3-2-1 backup guide.